Drill bit



May 20, 1952 J. l.. PILON ET A1. 2,597,669

DRILL BIT Filed Jan. 20, 195i In /enZ'ors l Josep/1 ILP/Yon A Beaq//el/ Patented May 20, 1952 kDRILL BIT Joseph L. Pilon and Aneae Beaulieu, North Bay,

Ontario, Canada,

assgnors to Inspiration Milling & Development Company Limited, Toronto, Ontario, Canada Application January 20, 1950, Serial No. 139,584 4 claims. (o1. 25a-72) in the annular working face of the bit to rotate on radial axes as the bit is rotated. This type of bit affords the presentation of a plurality of cutting elements under drilling which are moved into and out of cutting contact but each element is constantly worn at the same angle so that no new cutting edges on the element are presented. Additionally, the rolling cutters seriously minimize the cutting action as the cutting elements merely roll on the surface being cut.

The principal object of this invention is to provide an improved drill bit in which new cutting edges on the cutting elements are continually presented as the drill advances but in which the cutting elements are held rigidly and iixedly against displacement under bit rotation to bite into the surface under the full torque thrust of the drill to afford a sharper bit and an improved cutting action for faster cutting.

A further important object is to provide an improved cutting roller which can be easily and quickly secured in the Working face of the bit, will provide long life operation, and can be readily replaced on becoming worn.

The principal feature of the invention consists in mounting a plurality of cutting rollers in the annular face of a drill bit to rotate on axes perpendicular to the radii cutting said rollers.

A further important feature consists in forming the cutters as diamond-encrusted rollers with diamond chips forming the cutting elements.

A still further feature consists in forming the rollers to present their cutting elements below and outwardly peripherally of the annular Worklng face of'the bit.

Another feature resides in mounting the rollers for convenient replacement. Y

These and other objects and features will become apparent with reference to the following bit ofFigure 1.

cutting elements of Figures 1 and 2 showing the element as a diamond-encrusted roller.

Figure 4 is a very much enlarged-diagrammatic illustration showing the changing angles at which the diamonds are presented to wear on continually changing planes as the bit is axially advanced, the view showing progressive positions of a single diamond chip and the profile cut thereby.

Figure 5 is an enlarged fragmentary vertical sectional view taken on the line 5 5 of Figure 1 with only selected cutting edges depicted and illustrating the relative movement of the cutting roller and drill bit under axial bit movement and the profile cut by an individual diamond.

Referring to the accompanying drawings, we

' show the bit I of annular form presenting an the rollers Figure 3*"is a 'Perspective 'view of oneA annular working face 2. Formed in the annular working face ae a plurality of radial slots 3 which have on each side thereof, intermediate the width of the working face, auxiliary transverse slots 4 of somewhat lesser depth and opening into the slots 3.

The transverse slots 4 on opposite sides of each radialy slot 3 arein alignment to afford a mounting for the axles 5 of the cutters 6, shown particularly in Figures 2 and 3. These cutters are in the form of diamond-encrusted rollers wherein the cutting elements are small diamonds or diamond chips 'l embedded in the roller surface and presenting a plurality of cutting edges 3, shown particularly in Figures 4 and 5.

The diamond-encrusted roller cutters 6 are mounted in the radial slots 3 with their axles supported in the transverse slots 4, the bottom surfaces 9 of which are grooved to the contour of the axle to permit the ready turning of the rollers.

It will be seen on reference to Figure 2 that with the axles 5 in the transverse slots 4 the rollers are arranged to rotate on axes which extend circumferentially so that the rollers rotate in radial planes and radii l0 through the centre of the rollers form the right bisectors of. the axles.

Under drilling, as the pressure will always be upwardly on the rollers forcing the axles against the bottom bearing surfaces 9 of the transverse slots, no elaborate fittings or bearing surfaces need be provided opposite the bearing surface 9 in the slots 4, and it is sufficient to simply close the slots 4 with a suitable temporary flux ller l2 or other equivalent to maintain in position in their slots against It will be appreciated that in drilling the bit is rotated and as the drilling or cutting is effected it has a composite motion of circumferential movement and axial advancement.

Under pure rotative movement, that is, circumferential movement, the force acting through the reaction of the surfaces being cut o n the cutting elements 'l are substantially parallel-the axles 5 and there will be no torque imparted to rotate the rollers 6 by such parallel reactive thrusts under the circumferential bit movement.`

Under axial bit movement however the reactive thrusts of the surfacesengaged by the c utting element 'I will imparta torque about 'the axles 5 to rotate the rollers lli.

As shown in Figure 2, the rollers 6 are of a diameter to project the cutting elements 'l beyond both the outer and inner walls of the bit I as well as beyond the annular working face 2. Each cutting element 1, is provided with cutting edges 8 which therefore perform a vcutting action while being moved under axial bit movement through' 180 from a position with 'the cutting element within the inner wall of the VWorking face 2 vand intersected by a substantially horizontal radius to a position Without the outer bit wall and intersected by a radius.

Thus it will be seen, particularly with reference to Figure 5, that each cutting element Tis presented to the surface I3 b eing cut at'continually changing angles as the bit is, axially advanced.

It is to be again noted that ateach new angle that la cutting element is presentedthe cutting element is rigidly and fixedly held against the reactive thrust by the surfacebeing c ut while the bit is moving with pure rotative or circumferential movement so that the cutting edges 8 of each cutting'element 4will be Worn' in accordance with lthe' particular angular relation of the cutting element and the vsurface being cut. This is an extremely important feature, providing wear on the cutting elements along continually changing planes to continually provide new cutting edges 8 to maintain the cutting elements or diamonds sharp at all times and to provide more uniform Wear so that the diamonds will serve as useful cutting elements throughoutV their entire life.

This feature will be better] understood with particular reference to Figure 4 wherein the cutting` element 1 is illustrated rst vertically beneath the axle 5 'in solid lines'to be worn along a plane I 4. The cutting element is "shown in dotted lineat an angle a to the 'axle 5 vafter the bit has been advanced axially so" that thel particular cutting element illustrated has cutv the profile I5. In this intermediate dotted position it will be seen that the plane of Wear has changed under bit rotation to afford wear on the plane I S, providing a new cutting edge I1. In the lowermost position after the bit has been advanced axially still further the 'cutting velement is shown at an increased angle' b'relative vthe vertical from the axle 5. Here again the w'e'ar plane is different affording wear bnthe plane'il to provide further new cutting edges.

Figure 5 also traces the profile I5 cut'by a single cuttingelement 1 'under axial bit advancement and rotation of the rollerl through 90 showing again the different planes' of vwear occurring under different positions of the cutting element.

"The above action will be seen to maintain the diamonds sharp'at all 'times continually" presentingfneW-cuttirig' edges as' thebit is'advanced but 4. In ,a diamond drill b it., ai; angular ,wgiiing Asubstantially horizontal 4.v take out the ,wholecutter element and insert a replacement cutter.

It will be appreciated that, the maintaining of the diamond cutting elements 1 fixed during the ""actual circumferential drilling movement of the bit and arranging new cutting edges to be continuallypresented upon axial bit movement, a very desirablel cutting action will be provided, and ithas beenfound that a bit constructed in ac- 'cordance with my invention provides materially fasterhcutting than either conventional bits having' the cutting elements embedded in their working faces or having cutters mounted to rotate on radial axes.

It will'be understood that various modifications may be made in `the mannergof actually vmounting the cutting elements without 'departing from'the' scopel of our invention.

` -What we'claim as our invention is:

I1. In a diamond drill bit, an annular Working face, a plurality of rollers in the form of Adiamond-- encrusted cylinders` of uniform diameter ,and of a length to occuly an appreciableproportion of said annular worlinglface, 'said cylinders being mounted in said` annular working face vvthv their length vextending substantially in a vcircumferen- .tial directionto rotate upon axial movement of `the bit on circum'fercntiallyv extending axes perpendiculartoradiiofsaid'bit.

2. In a diamond drill bitranv annular working face, a plurality AofArollersv in thgform .of dia mond-encrusted cylindersof substantially uni- "form diameter and. of afsubstantiallength to occupy Van appreciable proportion of said annular fa'ce `and presenting multiple diamond `cutting points along their length, said .cylinders being 'mounted on concentric axlesfremovably set-in vsaid annular face .and extending substantially circumferentially'of A.the bit 3perpendii'gular lto radii of said bit and ,having as right bisectors radii of said bit, said axles permitting rotationof said rollers upon axialv movement of said .bit-to present new cutting points and maintaining said rollers against rotationupon circumferential bit movement to maintain cutting points in fixed cutting relation under such circumferential bit 'movement 3. VIn a vdiamond drill bit, a n annular working bit face, a'plurality of cutter rollers mounted o n axles `set in said 4 annular bit face and extending circumferentially to lsupport said rollers for r0- eachof said rollers being a cylinder substantially uniform in diameter for a substantial length to occupy an appreciable proportion of said annular bit face and having mountedon theperiphery thereof a plurality of diamond cutting lements formed with multiple cutting edgespr'e'sented beyond the cylindrical vperiphery in different ,directions, said cutting edges being presented'as rigidly fixed under circumferential bit movement and being presented at continually changing angles-under axial bit movement to wear 4on continually changing planes-whereby said diamond cutting elements are continually "sharpened through Iiil 0.1.1 .Said l1fi11sinsY planes as'aid bit i's'advanced through a 'surface 'bei`r 1g "cut face, a plurality of radial slots formed in said working face, aligned transverse slots formed in said annular working face and extending circumferentially from the sides of said radial slots, rollers in the form of uniform diameter cylinders of appreciable length substantially equal to the width of said slots and encrusted with diamonds and presenting multiple diamond cutting edges, said cylinders being mounted in said radial slots on concentric axles removably received in said aligned transverse slots to rotate in radial planes, the cutting edges of said rollers being presented beyond said annular Working face and beyond the inner and outer walls defining the inner and outer peripheries of said annular working face, said rollers being normally non-rotatable under circumferential bit movement but rotating under axial bit movement to .advance cutting edges to CII cut at continually changing angles whereby said edges are worn in continually changing planes to maintain said edges sharpened.

JOSEPH L. PILON. ANEDE BEAULIEU.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

